Image forming apparatuses include, for example, a printer, a facsimile machine, a copier, a plotter, and a multifunctional machine combining several of the functions of these apparatuses. As an image forming apparatus using a liquid discharge recording method that uses a recording head that discharges ink liquid droplets, for example, an inkjet recording apparatus is known.
Image forming apparatuses using the liquid discharge recording method perform image formation (hereinafter used as a synonym for recording, imaging, and printing) by discharging the ink droplets from the recording head onto a sheet being conveyed. Herein, such sheet is not limited to paper but includes any material to which the ink droplets and other liquids can adhere, such as an OHP (overhead projector) sheet, and is referred to also as a recorded medium, a recording medium, recording paper, a recording sheet, and so forth.
Image forming apparatuses using the liquid discharge recording method can be divided into serial-type image forming apparatuses which form an image by discharging liquid droplets from a recording head that moves in a main scanning direction, and line-type image forming apparatuses which form an image by using a line-type recording head that discharges liquid droplets while the head remains stationary.
As an example of the image forming apparatus as described above, a line-type image forming apparatus is known, as described above, which includes a line-type recording head including nozzle arrays arranged to cover the full width of the sheet being conveyed. The line-type recording head used in this case includes, for example, a plurality of short heads that themselves include arrays of nozzles for discharging liquid droplets, and which are arranged in the nozzle arrangement direction. This type of recording head is referred to as a multiple array head.
In the multiple array head as described above, ink is supplied to the plurality of heads. Further, ink is supplied to respective heads of the multiple array head from an ink tank generally through a flexible supply tube.
Since ink is supplied to the multiple array head through the flexible supply tube as described above, an equal number of the supply tubes is necessary, resulting in a complex tube system. Accordingly, it is not easy to assemble and maintain the tube system because of such complex tube arrangement.
Further, the supply tube must be released when changing the head, risking scattering ink and allowing air to get into an ink supply path. Further, ink may leak from a connecting portion between the supply tubes, and so-called slow-air-leak may occur, in which air leaks out gradually.